Building block



FIG. 1 is an upper front right perspective view of a building block,showing our new design;

FIG. 2 is a bottom view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is an enlarged right side elevation view thereof;

FIG. 5 is an enlarged left side elevation view thereof;

FIG. 6 is a front elevation view thereof; and,

FIG. 7 is a rear elevation view thereof.

The broken lines in FIG. 1 and FIG. 2 are for the purpose ofillustrating environmental structure and form no part of the claimeddesign.

CLAIM The ornamental design for a building block, as shown anddescribed.